1. Field of the Invention
This invention relates to a method of manufacturing a sintered body of silicon carbide which has a superior bending strength.
2. Description of the Prior Art
As a method of manufacturing a sintered body of silicon carbide, there have been known heretofore, for example, a method of adding to silicon carbide powders a sintering agent such as boron, carbon, boron carbide or aluminum nitride and then heat-treating the mixture at a temperature of 1800 to 2200 deg. C. in an atmosphere of an inert gas, and a method of adding to silicon carbide powders or silicon carbide fibers a binder such as polycarbosilane, polysilane or polysilazane and then heat-treating the mixture at a temperature of 1200 to 1500 deg. C. in an atmosphere of an inert gas.
However, in the former method, i.e., in the case of using a sintering agent, it is rather difficult to uniformly disperse the sintering agent into the antimelt-treated substance. Further, there is a problem in that it is difficult to obtain a sintered body of silicon carbide which is superior in heat resistivity.
On the other hand, in the latter method, i.e., in the case of adding a binder to the silicon carbide powders or silicon carbide fibers, the binder is decomposed during the heat treatment, and consequently the ratio of conversion into silicon carbide decreases; it is difficult to obtain silicon carbide of high density, resulting in a lowered bonding force among the powders or fibers. As a result, there is a problem in that the bending strength of the sintered body of the silicon carbide thus obtained decreases.
It is an object of this invention to solve the problems of the prior art methods and to provide a method of manufacturing a sintered body of silicon carbide which has a superior bending strength.